This invention relates to a method which executes a internal grinding of a workpiece by use of a grinding wheel, which is composed of abrasive grains of ultra hard material such as a cubic boron nitride (CBN).
Conventionally, in a case of executing the internal grinding, by use of the grinding wheel such as CBN grinding wheel (hereinafter called so) which is composed of the abrasive grains of the ultra hard material such as a cubic boron nitride and etc., there is a problem that just after the completion of dressing, the sharpness of the grinding wheel becomes dull and thereby several and/or several tens of workpieces are ground through the internal grinding in a manner that the ground hole is shaped in progressively narrowed toward the end, namely the cylindricity becomes poor. Thus, conventionally, the workpeice just after the dressing is inspected and selected by the man power. Otherwise, several and/or several tens of the workpieces are abolished just after the dressing, which is called a dummy work.